Don't get me wrong: Microsoft needs a tablet. Apple sold 3 million iPads in two months, and that was amid howls that it was overpriced and underfunctioning. The market for a thin but large, touch-screened thing-that-isn't-a-phone is clear, as an e-book reader, as a movie player, as a game pad, as a casual e-mail-and-Web device. Why rest a hot PC on your lap when you can balance a slender slab on your thigh? So what if that slab only does 85 percent of what the PC can do?

The debate at the core is whether you build a tablet using a low-powered but lower-featured mobile operating system, as Apple did, or whether you go whole hog with a full-fledged PC operating system. Although Microsoft has a new mobile operating system in the works, and has focused some research on tablet-specific operating systems, it is choosing to push for tablets that run the same operating system already found in netbooks, laptops and desktops. (Msnbc.com is a joint venture of Microsoft and NBC Universal.)

The very need for a distinction between tablets and PCs seems to trouble Microsoft. According to the current strategy, the tablet — or "slate," as Ballmer calls it — is a PC. The upside is evident (if short-sighted): It runs all the same programs as other computers.

But the multiple downsides need to be addressed:

1. The hardware required to run Windows 7 with full graphic support isn't thin or cool. Microsoft knows how to shrink Windows 7 down to a pretty small piece of software, and can run it on some low-powered machines, but that only works when the pretty graphical interface is stripped out.

The iPad's 1-gigahertz processor may seem weak compared to the 2- and 4-core chips that power our workhorse PCs, but nobody has ever complained about the iPad having lousy graphics. It's the lack of visual hiccups that makes us think it's something other than a "computer," and that's a good thing.

Even my friend Avram Piltch from Laptop Magazine, who wrote an essay defending Windows tablets, admitted that the cosmetic issue was not solved: "Users may have to initially accept a little more thickness, a larger battery, or a tad less endurance than they’d get with an iPad," he wrote, though he said these tradeoffs were worth it for the added functionality of a real PC.

2. The interface was designed for a mouse, keyboard and larger screen. I use Windows 7 every day, and when you have a mouse and a 15-inch screen, it's a very nice operating system. I can close or click open all the little pop-up messages, and can monitor all of the tiny icons in the system tray, no problem. Double-clicking, right-clicking, scrolling, alt-tabbing and F5'ing all come naturally to me in this environment,

But if the same interface was at the mercy of me and my clumsy fingers? This is not about Microsoft vs. Apple. It's about the importance of ditching the old interface — Windows or Mac — in order to give full reign to the newer, so-called "natural" interface.

3. PC multitasking is not the same as tablet multitasking. The solution to the interface problem is to create a whole layer of control and applications that are built for touch. But doing so tends to anger that two-faced beast known as multitasking.

When the iPad came out, a lot of people were complaining about its lack of multitasking. What they meant (mostly) was that they wanted to be able to play music from Pandora while reading a book in the Kindle app. The newest update for the iPhone 4 and iPhone 3GS bestows this ability, satisfying the majority of concerned parties.

On a PC (or Mac), various programs and system processes constantly line up to demand resources, often without your involvement. Slapping a smooth touch interface on top of that madness is futile.

How often are you distracted, on your PC, by a message that your Java is out of date? Or you need to download new virus definitions? Or, heaven forbid, that you haven't backed up your computer in 20 days? The minute your e-book-reading reverie is disturbed by such housekeeping nonsense, you may accidentally throw your Windows 7 tablet out the nearest window.

4. There aren't (m)any touch apps for Windows 7. One of the most troubling aspects to Ballmer's push for Windows 7 tablets is that there already are Windows 7 tablets. In fact, Microsoft has had nearly a decade to encourage developers to create programs for touch and stylus interfaces, with nothing — or next to nothing — to show for it. Microsoft didn't even see fit to release its own elegant suite of Windows 7 touch apps, built to demo the operating system's inherent touch support.

Ever since Bill Gates introduced the first stylus-controlled tablet PCs back in 2001, the door for developers has been open. But the fact that so few have walked through is surely a sign that Microsoft itself has not considered this a priority.

It's a shame that Microsoft hasn't focused more on its lighterweight operating systems. Last year, word of the so-called "Courier" tablet project leaked out. It was to be a two-screened, stylus- or finger-controlled wonder-tablet, and people were genuinely excited. But several months ago, Microsoft unceremoniously put the project to death.

Its great smart-phone hope, Windows Phone 7, meets all the requirements for a tablet interface. Yet last spring when I asked the head of that project about a tablet, he said that for the time being, the focus was solely on phones. (The fact that Windows Phone 7 has "phone" in its name is either a lack of foresight or a sure sign of Microsoft's determination to keep it telephonic.)

What we're left with is a generic lineup of Windows 7-based tablets from Dell, Samsung, Sony, Toshiba and others, the same people that regularly contribute to a generic lineup of Windows 7-based PCs.

But there's hope, because, in Ballmer's words, these tablets "will be very good for the kinds of scenarios that all of us are going to see for knowledge workers in the business that we serve that want to have something that works super well at work, but also supports their kind of personal interests as they travel."

I'm only joking. There is no hope for these tablets.

Catch up with Wilson on Twitter at @wjrothmanto chat about tech, cooking or touch interfaces — the touchier the better.